The present invention generally relates to a gas detecting device that detects the presence of a plurality of different kinds of gases.
As is known, various types of gas detecting devices have been proposed. For example, Japanese Laid-Open Patent Application No. 61-191953 discloses a gas detecting device in which a microheater formed by fine formation is used. The proposed gas detecting device has a single gas sensitive element, which is heated by a heater. The proposed gas detecting device is designed to detect a single kind of gas. It is possible that an output signal from the single gas sensitive element could be filtered by a filter which is attached to the gas detecting element. However, it is impossible to obtain output signals corresponding to different kinds of gases from the single gas sensitive element.
In order to detect the presence of different kinds of gases, it is possible that individual gas sensitive elements sensitive to different kinds of gas be used. However, the use of different gas sensitive elements leads to an increase in the manufacturing cost.